Jak2 exon mutation analysis(V617F) Real Time PCR

The JAK2 V617F test looks for one specific change in the JAK2 gene that is commonly found in a group of blood conditions called myeloproliferative neoplasms (MPNs). Haematologists use it when blood counts are persistently high or when a blood clot appears in an unusual place.

What the test looks for

The JAK2 gene carries instructions for a protein that helps control how the bone marrow makes blood cells. The V617F change sits in exon 14 of the gene. It is not inherited: it is acquired by blood-forming cells during a person’s life. When present, it switches the JAK2 signal on permanently, so the bone marrow makes too many red cells, platelets or white cells.

The V617F change is commonly found in:

• Polycythaemia vera, where the body makes too many red blood cells
• Essential thrombocythaemia, where the body makes too many platelets
• Primary myelofibrosis, where scar tissue gradually builds up in the bone marrow

The lab uses real-time PCR, a sensitive method designed to pick up this single change in the DNA from your blood or bone marrow cells.

Who might consider it

A doctor, usually a haematologist, may suggest this test if you have:

• A raised haemoglobin or haematocrit that stays high on repeat tests
• A persistently high platelet count without another explanation
• A blood clot in an unusual site, such as the veins of the abdomen
• An enlarged spleen or other findings that suggest an MPN

It is also used to confirm a diagnosis that is already suspected from other tests.

Before you book

The test uses a blood sample (or bone marrow, if your doctor has arranged a bone marrow sample). Our team can collect the blood at your home or office anywhere in Dubai, or you can visit our lab in Al Karama or Al Barsha 1. The lab asks for a signed consent form and your relevant medical history with the sample, as it does for all genetic tests. Results are usually ready in 3–5 days.

You do not need a referral to book, but because the result only makes sense alongside your full blood count and symptoms, we recommend doing this test with the doctor who is investigating your blood counts.

Understanding your results

The report says whether the JAK2 V617F change was detected or not detected.

• Detected: the finding supports a diagnosis of an MPN. Your doctor uses it with your blood counts, examination and sometimes a bone marrow test to decide which condition it is and how to manage it.
• Not detected: this does not rule out an MPN. Some people have changes elsewhere, for example in JAK2 exon 12, CALR or MPL. If your doctor still suspects an MPN, they may order further tests, such as the JAK2 exon 12–15 mutation analysis or a wider MPN gene panel.

Because this change is acquired, it is not passed on to children, and family members do not usually need testing because of your result. Always discuss the report with your haematologist before making any decision about treatment.